This invention is related to Patent Application entitled: "Electrical Terminal Construction", Ser. No. 523,318, filed Nov. 13, 1974.
This invention relates to improvements in electrical terminals of the solder lug or wall type, and is more particularly concerned with providing such terminals with means that will effect a more positive retention of electrical lead wires inserted therein preparatory to dip soldering.
As is well known in the terminal connector art, various structures and expedients have been utilized to mount and retain electrical terminal connectors on the associated bases. Among such structures are screws, rivets, sliding connectors, and clamps or clips of one sort or another. With the advent and now widespread use of printed circuits, and hence, of printed circuit boards, the need has arisen for providing improved terminals for connecting electrical wires or leads for the circuit boards.
Accordingly, the present invention is directed to providing an improved electrical terminal connector particularly suited for use with, or on printed circuit boards (but not necessarily limited thereto), which terminal is adopted to receive from one to five electrical leads or wires of various gauge sizes with the wires being of either stranded or solid construction.
Prior electrical terminals of the solder well type have been provided with wire-gripping fingers and have been reasonably successful in retaining larger gauges of electrical lead wires or bundles of lead wires. Often, however, individual small guage wires must be assembled with the terminals. Practical experience with prior solder well terminals has been a lack of satisfactory retention of the smaller wires so that they tend to become very easily dislodged or even drop out of the terminals in handling incident to various assembly and soldering operations. This apparently comes about because these solder well terminals are made from sheet metal as progressive die stamped and shaped articles in which the retaining fingers are subjected to the usual variables and tolerances which must be expected in any stamped sheet metal product. The forming dies necessarily have various tolerances and are subject to wear. Hence, although the retaining fingers may be produced with reasonable accuracy of wire-retaining convergence, it has been difficult to maintain such close tolerances, accuracy of mutual retaining conjunction of the prong tips, and sharpness for the smaller gauge wires.
It is to the overcoming of the foregoing and other deficiencies and disadvantages of the prior constructions that the present invention is directed. More particularly, by the present invention there is provided effective, highly satisfactory and reliable retention of even the finer gauge wires that have the axial strength to be thrust into engagement within the vertex of the retaining gauges of a solder well terminal. For this purpose the invention provides new and improved wire retaining tines in a solder well terminal.
The terminal connector in the embodiment is formed of spring brass or other suitable material of roughly .010 inches thick. It is preferably pretinned for easy soldering characteristics.
Tines or leaves are formed and positioned in the terminal connector to securely engage a wire inserted therein and windows or openings are formed in the body of the terminal to assure that a path for solder is provided for a firm mechanical and electrical connection between the wires and the terminal connector.
These tines are collectively bowed, that is, form an arc, towards the opposite side in a manner designed to engage even the smaller gauge wires and tightly hold them. This is done by bowing the tines at such a curvature that the end points of the tines preferably come into close contact with the opposite wall of the connector. The tines are preferably composed of four individual prongs with each prong being separate from and yet in close contact with the adjacent prongs. Each individual prong is also formed to be curved in cross section, as will be explained, thereby contributing to the strength and rigidity of the prong. It is because of this strength and rigidity that the wire can be held tightly, and thus be resistant to the removal forces found in the normal handling procedure existing in the assembly of the electrical components of which the terminal is part.
Serrations are also formed in the back of the terminal, much in the fashion of a series of louvers. These serrations serve as a gripping surface for gripping the wire on a side opposite that facing the tines, thereby positively retaining the wire(s) by a pincer-like action on two sides of the wire, by both the tines and the serrations.
The inventive terminal connector may be either manually or automatically inserted or mounted in the associated apertures of the printed circuit board. After insertion of the terminal in the associated boards, the terminal is securely retained therein by a unique lug construction as is described in the above cited U.S. patent aplication, Ser. No. 523,318.
The foregoing and other features and advantages of the invention will be apparent from the following more particular description of the preferred embodiments of the invention, as illustrated in the accompanying drawings wherein: